Iraq is being flooded with weapons despite human rights violations by all parties in the conflict there, and without any proper monitoring by the US and Britain over where the weapons end up, Amnesty International says today.

There is no clear accountable audit trail for some 360,000 small arms supplied to the Iraqi security forces, many by the US and UK, it says. Subcontracting makes the arms trade even less transparent. Among examples cited by Amnesty are the supply of 63,800 Kalashnikov assault rifles from Bosnia to Iraq and the dispatch via the UK of thousands of Italian Beretta pistols, many of which ended up in the hands of al-Qaida insurgents in Iraq.

"The easy availability of small arms and lack of accountability in Iraq has contributed to sectarian killings by armed groups, as well as torture and other ill-treatment; extra-judicial executions by Iraqi government forces and the continuing arbitrary detention of thousands of suspects by Iraqi soldiers backed by US armed forces since 2003," says Amnesty.

It adds: "Very serious failures have occurred in the effective management of huge quantities of weapons and munitions supplied to Iraq since 2003. While Iraqi officials ... have been primarily responsible, a significant share of the responsibility rests with the US and UK coalition forces and their contractors."

According to US state department figures this week, Iraq has signed more than $3bn worth of arms deals in the past two years. Amnesty estimates that more than 1m small arms have been sold to Iraq since the 2003 invasion and the Iraqi government plans to procure more than 250,000 from the US and China.

This trade would have been controlled, and the supply of weapons pouring into other conflict zones - notably Burma and Darfur in Sudan - prevented had an arms trade treaty been in place, Amnesty says.

Weapons are flowing into Darfur despite a UN embargo, it says in a 125-page report, Blood at the Crossroads, which sets out the case for a robust arms trade treaty due to be discussed at the UN next month. It says that on February 19 this year, two Chinese Fantan fighter jets were used in an attack on Beybey in Darfur and three large bombs were dropped on a settlement killing eight people, including children. The aircraft had recently been serviced by Chinese technicians and their Sudanese pilots allegedly trained in China to fly them.

Russia has agreed to supply 27 helicopters to Sudan, says Amnesty. Last year, Sudan listed its main arms suppliers as China, Russia, North Korea, Belarus, Indonesia, Iran and Malaysia.

Meanwhile, countries including China, Russia, Ukraine and Serbia have been providing huge quantities of arms to Burma despite human rights violations said by the UN to be widespread and systematic. UN arms embargoes continue to be flouted in Ivory Coast and Somalia, while arms supplies to Colombia, Guatemala, Guinea, Chad and Uganda show the "catastrophic human rights consequences of unrestrained arms trading", Amnesty says.

Kate Allen, Amnesty International's UK director, said: "Next month's decision at the UN is crucial. Governments around the world cannot go on ignoring the untold suffering and dreadful abuses caused by irresponsible global arms transfers. World leaders have to uphold their obligations on human rights and to move forward on an international arms trade treaty which is underpinned by the 'golden rule' on human rights."

Amnesty describes the golden rule as countries undertaking not to approve the supply of "conventional weapons, munitions, military equipment or assistance, where there is a substantial risk that such items will be used for serious violations of international human rights".

Last week, David Miliband, the foreign secretary, committed himself to pressing for an effective treaty, Amnesty says. But the proposal is opposed by countries such as China while others, including India, Pakistan and the US, are attempting to block, delay or dilute the plans, which would allow the trade in arms to continue unchecked, Amnesty says.